Elec Coil heat vs Heat Pump - Home Energy Pros2015-08-02T22:40:13Zhttp://homeenergypros.lbl.gov/forum/topics/elec-coil-heat-vs-heat-pump?commentId=6069565%3AComment%3A133017&feed=yes&xn_auth=noAdding electric resistance co…tag:homeenergypros.lbl.gov,2013-08-23:6069565:Comment:1351012013-08-23T02:57:54.439ZGeorge J. Nesbitthttp://homeenergypros.lbl.gov/profile/GeorgeJNesbitt
<p>Adding electric resistance coils in the ducts would likely have caused the problem discussed in the post; <span class="xg_avatar"><a class="fn url" href="http://homeenergypros.lbl.gov/profile/JimGunshinan" title="Jim Gunshinan"><span class="dy-avatar dy-avatar-48"><img alt="" class="photo photo" src="http://api.ning.com:80/files/5gmhwaVabu4eRAUm0oaC67M6uWZd774-I1jhPPQYWJeHRgGMjWzXOnXduQMcz2G1r**g46lEpeUSohMUmVj-u6IufxP8FqAh/494673804.jpeg?xgip=0%3A0%3A957%3A957%3B%3B&amp;width=48&amp;height=48&amp;crop=1%3A1"></img></span></a></span></p>
<h3><a href="http://homeenergypros.lbl.gov/forum/topics/how-do-we-make-energy-efficiency-sexy-or-at-least-interesting">How Do We Make Energy Efficiency Sexy, or at Least…</a></h3>
<p>Adding electric resistance coils in the ducts would likely have caused the problem discussed in the post; <span class="xg_avatar"><a class="fn url" href="http://homeenergypros.lbl.gov/profile/JimGunshinan" title="Jim Gunshinan"><span class="dy-avatar dy-avatar-48"><img class="photo photo" src="http://api.ning.com:80/files/5gmhwaVabu4eRAUm0oaC67M6uWZd774-I1jhPPQYWJeHRgGMjWzXOnXduQMcz2G1r**g46lEpeUSohMUmVj-u6IufxP8FqAh/494673804.jpeg?xgip=0%3A0%3A957%3A957%3B%3B&amp;width=48&amp;height=48&amp;crop=1%3A1" alt=""/></span></a></span></p>
<h3><a href="http://homeenergypros.lbl.gov/forum/topics/how-do-we-make-energy-efficiency-sexy-or-at-least-interesting">How Do We Make Energy Efficiency Sexy, or at Least Interesting?</a></h3>
<p>With your customer ending up with a higher electric bill.</p>
<p>Adding Solar often drives people to want to convert from gas to electric, solar installers often encourage this.</p>
<p>For smaller houses, and very energy efficient houses, and conservative occupants, switching to electric can be a good choice, but it increased the primary (source) energy consumption at the power plant (aprox 3x the energy at the power plant than used at the house). Of course heat pumps can lower the site energy with minimal impact on the source energy, and are almost always less expensive to run than propane.</p>
<p>Switching to ductless mini-splits eliminates the duct losses. Although air tight ducts in conditioned space have no loss either. The problem can be distribution, and many builders install small bath fans w&amp;w/o ducts to help distribute the heating / cooling. Having an energy efficient home will help make distribution easier.</p>
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<p>Have they, or are they doing any efficiency upgrades to the house to reduce energy use?</p> About the biggest joy I get f…tag:homeenergypros.lbl.gov,2013-08-11:6069565:Comment:1331102013-08-11T23:58:47.684ZJoseph Lamyhttp://homeenergypros.lbl.gov/profile/JosephLamy
<p>About the biggest joy I get from my mini-split is the gawks. First, they gawk, listening FOR the dang sound! They can FEEL the coolth or warmth spreading across the room, but they gawk and balk and twist their head to bend the ears and shrug. Age. Rock n' roll.</p>
<p>Then they gawk again at the electric eye scanning the room and aiming the flow to the warm spot in the summer cooling mode or the cool spot in heat mode. They'll open the door and time how long the eye takes to aim the fins at…</p>
<p>About the biggest joy I get from my mini-split is the gawks. First, they gawk, listening FOR the dang sound! They can FEEL the coolth or warmth spreading across the room, but they gawk and balk and twist their head to bend the ears and shrug. Age. Rock n' roll.</p>
<p>Then they gawk again at the electric eye scanning the room and aiming the flow to the warm spot in the summer cooling mode or the cool spot in heat mode. They'll open the door and time how long the eye takes to aim the fins at the idiot by the barn door grinning! </p>
<p>But the best gawk is the utility bills where the tiny little toe-print barely scratches the checkbook. If there's solar on the roof, one guy gets home, walks through the comfy house to the back door, opens it and watches the meter spin...BACKWARDS! "Ha printin money while I'm makin bacon!' </p>
<p>Just the de-humidification feature of the mini-split is a real comfort booster here in Seattle about 20 or 30 days a year in a climate where the actual cooling is needed only a few days by the squeamish finicky persnickety sickos like me, geezers on pills like me or gorgeous young porn stars who are convinced the sun rises to splay THEIR shimmering alluring beauty, like my young room-mate:)</p> The add-on electric heat coil…tag:homeenergypros.lbl.gov,2013-08-11:6069565:Comment:1330172013-08-11T23:10:30.173ZJoseph Lamyhttp://homeenergypros.lbl.gov/profile/JosephLamy
<p>The add-on electric heat coil has morphed into a ductless heat pump that eliminates duct loss, pressure-related convective losses associated with both the propane 80%'er at best before duct losses whack it and also the hapless unitary heat pumps that were noisy blends of old technologies and centralized mistakes of last century. Dump the 80% er, the tank and the smell. Drop the ducts, seal the penetrations. Run the whispering suit-case. With the sun.</p>
<p>I can't blame them for wanting to…</p>
<p>The add-on electric heat coil has morphed into a ductless heat pump that eliminates duct loss, pressure-related convective losses associated with both the propane 80%'er at best before duct losses whack it and also the hapless unitary heat pumps that were noisy blends of old technologies and centralized mistakes of last century. Dump the 80% er, the tank and the smell. Drop the ducts, seal the penetrations. Run the whispering suit-case. With the sun.</p>
<p>I can't blame them for wanting to avoid the expense and penalties inherent in that old time unitary, ducted heat pump- noisy, needs back-up, expensive! But look at mini-splits for significantly higher HSPF, better than anything in the strip heat arsenal, like COP of 3.8. handling low exterior temperatures without need for backup, invertor driven to maximize efficiency and minimize racket while eliminating health, safety and environmental issues. and running off ~ 450 to 1000 watts in Cali winter, 2 - 4 more panels of 250 watts each worth to go net zero. Why not go for the whole NINE yards?</p> Strip heaters in ductboard? T…tag:homeenergypros.lbl.gov,2013-08-11:6069565:Comment:1328272013-08-11T16:47:07.177ZBob Blanchettehttp://homeenergypros.lbl.gov/profile/BobBlanchette
<p>Strip heaters in ductboard? That's just hack work IMHO.</p>
<p>Strip heaters in ductboard? That's just hack work IMHO.</p> I have seen lots of heating e…tag:homeenergypros.lbl.gov,2013-08-11:6069565:Comment:1324892013-08-11T02:46:14.452ZEric Kjelshushttp://homeenergypros.lbl.gov/profile/EricKjelshus
<p>I have seen lots of heating elements melt though duct board when breaking apart. I like to put long time sequencers when putting in back up strip heat so it takes a very long time to turn on. You are very right about over sizing strip heat - 3-4 times over sized is norm. 8 KW strip heat in a 400 sf is very common I have put back 3 KW after sealing and will last a long time</p>
<p>I have seen lots of heating elements melt though duct board when breaking apart. I like to put long time sequencers when putting in back up strip heat so it takes a very long time to turn on. You are very right about over sizing strip heat - 3-4 times over sized is norm. 8 KW strip heat in a 400 sf is very common I have put back 3 KW after sealing and will last a long time</p> Sequencers and limit switches…tag:homeenergypros.lbl.gov,2013-08-11:6069565:Comment:1324852013-08-11T02:07:27.119ZBob Blanchettehttp://homeenergypros.lbl.gov/profile/BobBlanchette
<p>Sequencers and limit switches are the high failure items, they are marginal capacity for the high amp load. Elements rarely fail. Contactors last much longer but tend to be noisy when switching. Crappy ductwork and high static pressures will cause heating elements to switch off on high limit. Heating capacity is often oversized, many houses will heat fine with 10KW if decently insulated.</p>
<p>Sequencers and limit switches are the high failure items, they are marginal capacity for the high amp load. Elements rarely fail. Contactors last much longer but tend to be noisy when switching. Crappy ductwork and high static pressures will cause heating elements to switch off on high limit. Heating capacity is often oversized, many houses will heat fine with 10KW if decently insulated.</p> this is why most electric st…tag:homeenergypros.lbl.gov,2013-08-11:6069565:Comment:1327312013-08-11T01:44:28.264ZEric Kjelshushttp://homeenergypros.lbl.gov/profile/EricKjelshus
<p>this is why most electric strip heat do not work after 5 years. The worst is very high Static pressure system or lack of return systems, I just can not keep all parts working with on off and high amps. On a 4 ton drive system I see 25 KW of strip heat there is not the air flow to keep all of them on at same time. The builder likes the install price and the building owner can not pay the heat bills. </p>
<p>this is why most electric strip heat do not work after 5 years. The worst is very high Static pressure system or lack of return systems, I just can not keep all parts working with on off and high amps. On a 4 ton drive system I see 25 KW of strip heat there is not the air flow to keep all of them on at same time. The builder likes the install price and the building owner can not pay the heat bills. </p> Few electric heaters of any t…tag:homeenergypros.lbl.gov,2013-08-11:6069565:Comment:1326392013-08-11T00:23:36.700ZBob Blanchettehttp://homeenergypros.lbl.gov/profile/BobBlanchette
<p>Few electric heaters of any type have flow switches for lack of airflow. Most use thermal limit switches mounted near the elements.</p>
<p>Few electric heaters of any type have flow switches for lack of airflow. Most use thermal limit switches mounted near the elements.</p> I applaud your customer for w…tag:homeenergypros.lbl.gov,2013-08-09:6069565:Comment:1321472013-08-09T17:03:02.940ZJames Whitehttp://homeenergypros.lbl.gov/profile/JamesWhite
<p>I applaud your customer for willing to go without air conditioning in California. It is great that they are adding solar, but hopefully they are willing to buy some conservation carrots to go along with their solar candy.</p>
<p>It is difficult to answer your question regarding the feasibility of adding an electric heating coil without knowing the type of existing propane furnace, physical space limitations, tightness of the existing duct system, air flow limitations, and the size of the…</p>
<p>I applaud your customer for willing to go without air conditioning in California. It is great that they are adding solar, but hopefully they are willing to buy some conservation carrots to go along with their solar candy.</p>
<p>It is difficult to answer your question regarding the feasibility of adding an electric heating coil without knowing the type of existing propane furnace, physical space limitations, tightness of the existing duct system, air flow limitations, and the size of the existing electrical service to the home. Adding 10 kW of heat (32,000 BTU/Hr / 3,413 BTU/kWh) may require upgrading the size of the electric service from the electric utility. Old forced air systems are often leaky and inefficient, especially if the ducts run through an unconditioned attic or crawl space. The older furnace also may not be set up to simply bolt on an electric coil section. To prevent a fire, the electric coil section will need a flow switch to turn off the heater if no air flow is detected. </p>
<p>Would it be possible to install wall mounted heaters instead? That way they could provide heat only to the rooms that need it, while keeping the doors closed to the other rooms. </p>
<p>A gallon of propane contains approx. 91,600 BTUs of heat. Dividing this by 3,413 BTU/kWh means that there are approximately 28 kWh of raw energy in a gallon of propane. The heater is not 100% efficient, so you have to multiply this value by the system efficiency to determine the useful energy in a gallon of propane. An 80% efficient furnace would have 21.5 kW of useful energy per gallon. Don't forget to include the energy used by the pilot light in estimating the overall efficiency of the propane furnace. </p>
<p>If propane costs $3.50 per gallon, the equivalent cost per kWh would be:</p>
<p>$3.50/Gallon x 3,413 BTU/kWh / (91,600 BTU/Gallon x 80% Eff.) = $0.16 per kWh</p>
<p>If their electrical costs are anywhere near this high, they should keep the propane for back-up, and install a mini-split heat pump to provide a majority of their heating needs. The mini-split is not cheap, but neither is $1,200 per year propane bill.</p> In our mid-Atlantic region, $…tag:homeenergypros.lbl.gov,2013-08-09:6069565:Comment:1319942013-08-09T14:31:16.984ZEd Minchhttp://homeenergypros.lbl.gov/profile/EdMinch773
<p>In our mid-Atlantic region, $3.90/gallon propane in an 80+ heater is the same cost to heat as 15¢ kWh electricity. Higher in a more efficient heater.</p>
<p>True that the electric strip is cheap to install, but until propane gets a bit more expensive (it is below $3 here) don't do anything.</p>
<p>And even though a heat pump is more expensive to install, it will heat so cheaply that it will pay back quickly - you should do the calculations based on your costs. Then he will have air…</p>
<p>In our mid-Atlantic region, $3.90/gallon propane in an 80+ heater is the same cost to heat as 15¢ kWh electricity. Higher in a more efficient heater.</p>
<p>True that the electric strip is cheap to install, but until propane gets a bit more expensive (it is below $3 here) don't do anything.</p>
<p>And even though a heat pump is more expensive to install, it will heat so cheaply that it will pay back quickly - you should do the calculations based on your costs. Then he will have air conditioning even though he doesn't want it, but at re-sale time he may be happy he has it.</p>